Gear Doors - Popped Breaker

[Roger]

Has anyone seen this happen before:
Gear up cycles until it is time for the rear doors to close. At that point they just stay open, and eventually the circuit breaker pops. Reset the breaker with the gear handle still in the up position and nothing happens, but eventually breaker pops again. Reset the breaker and put handle down, gear locks down and all doors close and lock. Tried it several times, and always the same thing.

I am assuming that the breaker pops perhaps due to a heat build up with the pump running for a minute or more?

Had it up on jacks and it will not repeat it in the shop.


1980 - 337H

Any help would be greatly appreciated

tks/Roger

[Kim Geyer]

Roger
Check the nose strut for proper inflation. If it is low on pressure it won't extend all the way and it won't go all the way in the well.
Have had it happen several times on our airplanes. If thats fine look for a broken wire or a bad switch. The main gear up switches ar easy enough to check the nose gear switch is a little harder to get to.
Hope this helps
Kim

[Roger]

Kim - Thanks , I will check those issues. The under inflation is perhaps most promising, as the nose wheel strut bushing (O-ring) was replaced just before this began to happen. I'll post the results.

Meanwhile it is snowing so hard outside, I think I'll wait a day before I test it.

Roger

[Pete Somers]

Roger

The gear motor cuts out on pressure not on gear position.
If the gear motor continues to run although the doors are not closed means one of two things.

1. The pressure switch is intermittant
2. The HYD power pack is not able to build up to the 1500 psi to cut off.

I assume that you have a amber up light on even though the doors are not closed.
If you do that means the uplock switches are ok and the door control valve is not operating or the door lock valve is sticky.

Make sure all the downlock switches are in good condition and work freely and do not leak across the COM to the NO contacts.

Lots of things to have a look at but these would stop the doors from closing

Let me know how you get on

Regards
Pete

[Pete Somers]

Roger

When i wrote the downlock switches, i DO mean the downlock switches.

Just to make that plain to you.

Cheers
Pete

[Kim Geyer]

Roger
Where do you keep your plane when in Fla ?

[Roger]

Kim

Have a problem in FL finding a good T-hanger around St. Augustine. Keep it there and at Craig at times. Number 90 on the list for a hanger at St. Augustine, Number 18 at Palatka. I have a T-hanger for it at ART in NY.

Roger

[Mark Hislop]

Roger:

I had exactly the same problem as you did. The gear doors would not close in flight, and eventually the pump CB would trip. When I had the plane jacked up, everything worked as it should.

In my case, the problem was a shim under one of the Main LG downlock switches had slipped out. The LG would "make" the switch when on the gound, but the air loads on the LG in flight kept the LG from "making" the switch. We put the shim back in place, tightened down the switch, and it all worked again.

Mark